The present invention relates to the field of integrated circuit memory technology. More specifically, the present invention provides a compact nonvolatile memory cell in which a write control line is directly coupled to a tunnel diode of the memory cells, and techniques of operating, programming, and erasing such a memory cell to enhance the reliability and service life of the memory cell.
Memory cells are used in the implementation of many types of electronic devices and integrated circuits. These devices include microprocessors, static random access memories (SRAMs), erasable-programmable read only memories (EPROMs), electrically erasable programmable read only memories (EEPROMs), Flash EEPROM memories, programmable logic devices (PLDs), field programmable gate arrays (FPGAs), and application specific integrated circuits (ASICs), among others. Memory cells are used to store the data and other information for these and other integrated circuits.
As integrated circuit technology and semiconductor processing continue to advance, there is a need for greater densities and functionality in integrated circuits, which are often determined in a large part by the size of the memory cells. Therefore, it is desirable to achieve memory cells with smaller cell sizes. Further, it is desirable that the memory cells have improved operating characteristics, such as lower power consumption, nonvolatility, greater device longevity, improved data retention, better transient performance, superior voltage and current attributes, and improvements in other similar attributes.
There is further a need to provide techniques for programming and erasing the memory cells reliably. For example, during the program operation, unselected memory cells which are not to be configured should be left undisturbed. There is further a need for improved techniques of evaluating the physical characteristics of nonvolatile memory cells. These physical characteristics or properties are important in the determination of an integrated circuit's service life and reliability. These measurements are also useful for study and use in improving memory cells.
As can be seen, improved memory cells and techniques for operating, programming, and erasing these cells are needed. Improved techniques are also needed for increasing the reliability and longevity of these memory devices.